The broad objective of the proposed research is to develop a novel methodology for creating oral and inhalation vaccines. This methodology will utilize the techniques of molecular biology to create fusion proteins that contain two partners: a carrier domain and a vaccine domain. The carrier domain will be a modified and non-toxic variant of botulinum toxin that possesses the ability to cross gut and airway epithelial cells to reach the general circulation. The vaccine domains will be non-toxic polypeptide fragments obtained from tetanus toxin, diphtheria toxin and pertussis toxin. Each of these fragments will have the ability to evoke neutralizing antibodies and therefore resistance against the parent toxins. Initially, the goal of the work will be to create monovalent vaccines (i.e., carrier plus a single immunogen). If this succeeds, a subsequent goal will be to create polyvalent vaccines (i.e., carrier plus a string of two or more immunogens). Generally speaking, experiments will be conducted in a logical progression of steps. The major steps will be: a.) construction of fusion genes that encode carrier and immunogenic components, b.) expression and isolation of the chimeric proteins, c.) evaluation of each putative vaccine to determine whether it crosses gut and/or airway epithelial cells of laboratory animal and human origin, d.) testing of each chimeric vaccine for toxicity when assayed in vitro or in vivo, and e.) testing of each chimeric vaccine to determine whether it will evoke systemic resistance when administered orally or by inhalation to laboratory animals. To be gauged successful, a monovalent or polyvalent vaccine must be able to evoke resistance to at least 1,000 lethal doses of each immunogen in the compound. In the aggregate, the data from this work should indicate whether any particular carrier-immunogen conjugate is worthy of further consideration as a potential human vaccine. If successful, the work should culminate in the generation of monovalent and polyvalent vaccines against tetanus, diphtheria and pertussis toxins. In addition, the work should establish a general approach that could be used to create oral and inhalation vaccines against a broad array of human diseases.